Non-hazardous ketone peroxide compositions

ABSTRACT

Hazards from exposure to heat and reduction in effectiveness during storage of lower alkyl ketone peroxides such as methyl ethyl ketone peroxide are ameliorated through the combination of a heat desensitizing solvent having a boiling point between about 185*-225* C, for example an ester such as ethyl benzoate, and a stabilizer selected from vinyl pyrrolidone and polyvinyl pyrrolidone.

United States Patent Leveskis et a1.

NON-HAZARDOUS KETONE PEROXIDE COMPOSITIONS Inventors: Newton G.Leveskis, Walnut Creek;

Charles B. Abma, Oakland, both of Calif.

Argus Chemical Corp., Brooklyn, NY.

Filed: Dec. 8,1971

Appl. No.: 206,173

Related US. Application Data Division of Ser. No. 702,783, Feb. 5, 1968,Pat. No. 3,702,869.

Assignee:

US. Cl. 260/610 A, 252/186 Int. Cl. C07c 73/00 Field of Search 260/610SK, 610 A;

References Cited UNITED STATES PATENTS 11/1972 Leveskis et al. 260/610 A[111 3,867,461 [451 Feb. 18,1975

FOREIGN PATENTS OR APPLICATIONS 1,072,728 6/1967 Great Britain 260/610 A1,050,841 12/1966 Great Britain 260/610 SC Primary Examiner-BernardHelfizn Assistant Examiner-W. B. Lone Attorney, Agent, or Firm-Townsendand Townsend [57] ABSTRACT 5 Claims, No Drawings NON-HAZARDOUS KETONEPEROXIDE COMPOSITIONS This is a division, of application Ser. No.702,783, filed Feb. 5, I968, now US. Pat. No. 3,702,869.

This invention relates to storage stable and heat desensitized alkylketone peroxides. More particularly, it relates to lower alkyl ketoneperoxides in combination with certain miscible solvents and pyrrolidonestabilizers for rendering the ketone peroxides storage stable and heatdesensitized.

In the preferred embodiment the invention provides a lower alkyl ketoneperoxide composition containing a solvent that is miscible with theorganic peroxide and which has a boiling point about 185-225 C. Thesolvent falls categories: one of the following categories; esters,aldehydes, ketones, hydrocarbons, halogenated hydrocarbons, andepoxides. Use of a sufficient amount of any member of this group havingthe requisite boiling point has been found to significantly reduce thecapacity of the ketone peroxide to violently decompose upon exposure toheat.

In addition to the heat desensitizing solvent, a storage stabilizerselected from vinyl pyrrolidone and polyvinyl pyrrolidone may beincluded. When added in an effective amount, it has been found thatdecomposition of the ketone peroxide of the type that liberates gaseousby-products or decreases effectiveness of the peroxide in terms oflengthened gel times of monomers initiated therewith is substantiallyeliminated. Either the heat desensitizing solvent or the stabilizer canbe used along with the advantages contributed by each being obtained, orthey may be used together to concurrently obtain the advantages of thetwo additives.

The prior art discloses the advantages of incorporating certain solventswith alkyl ketone peroxides. The prior solvents suggested have generallybeen limited to monohydric alcohols and related polyol materials. Thepresent invention is based upon the discovery of a wide group ofmaterials of differing chemical structure, i.e., they are not alcoholsand glycols as noted above, which can be used to obtain equal andsuperior results to the hydroxy type solvents previously used.

Similarly, it has been previously reported that certain pyrrolidoneadditives were advantageously added to ketone peroxides to stabilizethem during periods of storage. The present invention is based upon thediscovery that vinyl pyrrolidone and polyvinyl pyrrolidone, which havenotheretofore been used as ketone peroxide stabilizers, aresignificantly superior as stabilizers compared with the pyrrolidoneswhich have been used in the past.

The solvent and stabilizer materials of this invention areadvantageously used with organic ketone peroxides, preferably thosealkyl ketone peroxides having relatively low molecular weights. Includedwithin this present invention is formed as a coreaction product ofmethyl ethyl ketone, 2,4-pentanedione, and hydrogen peroxide. Thisketone peroxide composition is more fully described and claimed incopending application, Ser. No. 473,855 filed July 21, I965, nowabandoned.

The amount of heat desensitizing solvent incorporated may vary to someextent depending on the particular ketone peroxide composition, itsactive oxygen content and the amounts of other optional elements such asplasticizers and other solvents which may be present. In general, forcommonly encountered ketone peroxides of commerical significance theheat desensitizing solvent will constitute at least about 3% by weightof the composition, and preferably about 525% by weight of thecomposition. There is substantially no upper limit to the amount of heatdesensitizing solvent which could be used if desired, ranging up to andmore of the composition.

Recently, a test known as a pressure vessel test (PVT) has beensuggested in the organic peroxide industry in an attempt to standardizewhat is meant by heat sensitivity of an organic peroxide. This testassesses the rate and amount of energy generated in a perox idedecomposition and is measured by the size of an aperture needed to ventthe decomposition vapors and prevent the rupture of a standard pressuredisc upon rapid heating. There is some agreement in the industry to theproposition that with the use of a standard vessel and a standard rateof heating of peroxide in the vessel, the maximum aperture size thatshould be tolerated in order to classify an organic ketone peroxide assafe with respect to the application of heat thereto, is a l0 millimeterdiameter aperture. It is likely that the preferred practice of thepresent invention will be to select a heat desensitizing solvent in anamount sufficient to permit the use of a l0 millimeter or smallerdiameter opening in the rupture discs used in the performance of thePVT. Use ofa solvent belonging to one of the noted groups and having therequisite boiling point in an amount of about 5-25% by weight will ingeneral achieve this'goal.

In the case of the storage stabilizing vinyl pyrrolidone or polyvinylpyrrolidone, the amount used for commercial purposes will generallyconstitute at least about 0.5% by weight of the composition. Optimumresults have so far been observed with the stabilizer added toconstitute about 2% by weight of the formulation. The vinyl pyrrolidoneand polyvinyl pyrrolidone of this invention are particularly effectivein substantially eliminating decomposition of the ketone peroxides ofthe type that liberates gaseous by-products. In this regard, packagingof ketone peroxide is frequently accomplished in plastic containers suchas polyethylene bottles. In the absence of the present stabilizers,during a period of normal storage gaseous by-product is generatedcausing the container to bulge and distort to a considerable extent. Bycontrast storage of ketone peroxide compositions with the presentstabilizers have been shown to result in no gassing or distortion of thecontainer. In addition, ketone peroxides which included previously usedstabilizers upon use after storage have been shown to require lengthenedtime for causing gelling of monomers. In the experimental work to bedescribed hereinafter it will be demonstrated that the presentstabilizers succeed in retaining substantially the same short length oftime needed to gel a monomer after periods of storage as initiallyrequired when in a freshly synthesized-condition.

In addition to ketone peroxide, heat desensitizing solvent, and storagestabilizer, any of the other usual components used in ketone peroxidecompositions may optionally be included. For example, plasticizers suchas the phthalate ester like dimethyl phthalate, dibutyl phthalatc andthe like may be incorporated. Another common component in suchcompositions is water. Where flame resistance is desired, a suitableamount of water may be included in accordance with the teachings ofcopending patent application, Ser. No. 584,608 filed Oct. 5, 1966, nowUS. Pat. No. 3,507,800. Emulsifying agents such as detergents is anothertype of ingredient which may optionally be included where a homogenousnon-separating composition in a paste or fluid form is desired. Theamounts and types of these optional additives are well-known in the artand the present invention is in all ways consistent with this prior bodyof knowledge.

The amount of ketone peroxides in the composition is open to widevariation. As a practical matter, most commercial compositions willcontain sufficient ketone peroxide to provide an active oxygen contentin the final product of about 9.0l2.5%. I

Any solvent having a boiling point between about 185 C and 225 C that ismiscible with the ketone peroxide will achieve the desired heatdesensitization of the organic peroxide. It will also permit preparationof a formulation which tolerates a rupture disc with an opening of 10millimeters or less in the PVT. These solvents are esters, aldehydes,ketones, hydrocarbons, halogenated hydrocarbons or epoxides. Typicalexamples of suitable solvents within these categories are as follows:

Boiling ESTERS Point. C.

Benzyl acetate 213.5 Benzyl propionate 220.2 Butyl caproate 207.7Ethylene glycol dipropionate 21 1.2 Heptyl propionate 210.0 Methylbenzoate 199.5 Methyl phenyl acetate 220.0 Octyl acetate 210.0 2-Ethylhexyl acetate 199.0 lsopropyl benzoate 218.5 Propyl caprylate 226 4Trieth 1 phosphate Ethyl enzoate Ethyl octoate Methyl decanoate BoilinAmyl benzene lso amyl benzene Decaltn 193.3 o-Diisopropyl benzene 210.0n-Diisopropyl benzene 202.0 n-Dodecane 214.5 2,4. 5,7-tetramethyl octane208.0210.0 n-amyl toluene 199.5 1,2, 3,4 tetramethyl benzene 205.0 3.5diethyl toluene 198.0200.0 Hexahydronaphthalene 207.0208.0

Boiling HALOGENATED Point,C. HYDROCARBONS Phenyl trichloride 200.73-bromo-o-Xylene 213.0-214.0 4-bromo-o-xy1ene 2140-215 0Z-bromo-m-xylene 206.0 4-bromo-m-xy1ene 205.0-207 0 5-bromo-m-xy1ene204.0 o-dibromobenzene 221 0-222 0 p-dibromobenzene 1,4-dibromobutane1970-1980 l.1-dibromo-2.2-dich1oro ethan 195.0-2000 Bromo octane 201.5 YTetra bromo ethylene 226.7 1.2.3-trich1oro benzene 213.0 1.2.4-trich1orobenzene 215.0216.0

Comment:

To illustrate the effectiveness of such solvents, a series of ketoneperoxide compositions were prepared with various solvents as shown inthe table below. The methyl ethyl ketone peroxide composition was astandard commercial type of formulation including about 60% methyl ethylketone peroxide and 40% dimethyl phthalate. To a series of samples, aportion of the following solvents was added thereto to constitute byweight of the formulation. All of the samples were tested in PVTapparatus. The size of the disc opening required to avoid rupture duringthe test is indicated in the table below:

TABLE 1 Methyl Ethyl Ketone Peroxide Boiling PVT Disc Solvent AddedPointC Size(mm.)

None (Control) 2800* 24.0

Boiling point of dimethyl phthalute 1n the following cases, heatdesensitizing solvents were added to different ketone peroxides asindicated with the PVT results as shown:

Coreaction product of ZA-pentanedione. methyl ethyl ketone, and aqueoushydrogen peroxide* Heat Desensitizing Solvent Amount PVT None 24 EthylBenzoate 10 9 90% Bis-( l-Hydroxy Cyclohexyl) Peroxide 10% dimethylphthalate Heat Desensitizing Solvent Amount PVT None 1 1 Ethyl Octanoate10 5 (replacement for the dimethyl phthalate) Ethyl Amyl Ketone PeroxideHeat Desensitizing Solvent Amount PVT None 5 Ethyl Octanoate 10 1Preparation in accordance with patent application Ser'. No. 471.855Filed July 21. 1965. I

"Preparation in accordance with US Pat. No. 3.151.170.

LII

7 a The above results show the advantages of the addivents fallingoutside of the critical boiling point range of this invention (l225 C),in which cases the PVT values were in the relatively less safe range ofsubstantially greater than 10 approaching the control methyl ethylketone peroxide composition which has a PVT value of 24 in the absenceof any desensitizing solvent. Forexample butyl benzoate is an estermiscible with the methyl ethyl ketone peroxide composition but itsboiling point is 249 C, considerably above the upper limit of 225 C ofthis invention and its PVT value was the same as the control peroxidecomposition.

The following results illustrate the effect of variation inconcentration of the heat desensitizing solvents of this invention. Atypical methyl ethyl ketone peroxide formula* was again selected towhich varying concentrations of ethyl benzoate and ethyl octanoate wasadded. The effect on PVT results is as follows:

Approximately (0% methyl ethyl ketone peroxide and 40% dimethylphihnlnte.

Comment:

From the above it can be seen that a minimum of about 3% by weightofheat desensitizing solvent is needed where a PVT value of about 10 orless millimcters in disc opening diameter is desired.

Concentration on the order of 5-10% and up to about 25% by weight ofheat desensitizing solvent will generally provide optimum results interms of heat desensitization and avoidance of overdilution andreduction of the active oxygen content of the formulation.

To illustrate the advantages of the present vinyl pyrrolidone andpolyvinyl pyrrolidone stabilizers during storage the followingexperimental work is offered: Two organic ketone peroxide compositionswere made up with the following materials:

l2-Parts Methyl Ethyl Ketone 3-Parts 2.4-Pentanedione IS-Parts 50%Hydrogen Peroxide lfi-Parts Hcxylene ('llycol 4,5 Parts H ion ExchangeResin Composition B:

lZ-Parts Methyl Ethyl Kelone 3-Pnrts ZAPentunedionu l5-Parts 50%Hydrogen Peroxide l5-Parts Methyl Carbitol 4.5 Parts H lon ExchangeResin The materials were allowed to react overnight (17 hours) afterwhich the reaction product was filtered and adjusted to a pH of 5 withpyridine.

T 6 pounds of e ach product, 50 grams of stabilizer was added. Thestabilized formulations were maintained at room temperature for a periodof 13 /2 months. The pH, and time to gel of a typical polyester monomerwere compared at the start and end of the test. Results are as follows:

composition containing at least about 0.5% by weight of stabilizerselected from the group consisting of vinyl Gel Time Gel TimeFormulation & Stabilizer pH Start' pH End Start End A.N-methyl-Z-pyrrolidone 5 3.5 21 min. min. B. N-methyl-Z-pyrrolidone 5 418 min. 23 min. A. 'Polyvinyl Pyrrolidone* 5 '4.5 '21 min. '21 min." WWe 1 r B. Polyvinyl Pyrrolidone* 5 4.5 18 min. 20 min. A. VinylPyrrolidone 5 4.5 21 min. 21 min. B. Vinyl Pyrrolidone 5 4.5 18 min. 20min.

2-week period as well as gelling times for a typical polyester monomerare shown in the table below:

*Viscosity grade K-lS average molecular weight 10.000. Equivalentresults areobtained with otherviscosity grades.

20 pyrrolidone and polyvinyl pyrrolidone to substantially inhibitdecomposition of said ketone peroxide of the type that liberates gaseousby -produ'cts or decreases ef- Again the stabilizer was added toconstitute 2% by weight of the formulation. 29mm??? At the end of the2-we'ek period of the test, the bottles containing N-methyl2-pyrrolidone were bulged out at the top and bottom of the bottle. Thebottles were distorted and no longer depressible by hand pressure. Inthe case of the bottles containing vinyl pyrrolidone and polyvinylpyrrolidone stabilizers, there was no bulging or distortion of thepolyethylene bottles and the bottles were depressible easily by handpressure.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it is understood that certain changes andmodifications'may bepracticed within the spirit of the invention aslimited only by the-scope of the appended claims.

lizer is polyvinyl pyrrolidone and constitutes about 2 percent by weightof said composition.

5. A storage stable lower alkyl ketone peroxide com- .position inaccordance with claim 1 wherein a said ketone peroxide is a coreactionproduct of methyl ethyl ketone, 2,4-pentanedione, and hydrogen peroxide.

1. A STORAGE STABLE KETONE PEROXIDE COMPOSITION FORMED FROM AT LEAST ONEALKYL OR CYCLOALKYL KETONE HAVING UP TO EIGHT CARBON ATOMS, SAID KETONEPEROXIDE COMPOSITION CONTAINING AT LEAST ABOUT 0.5% BY WEIGHT OFSTABILIZER SELECTED FROM THE GROUP CONSISTING OF VINYL PYRROLIDONE ANDPOLYVINYL PYRROLIDONE TO SUBSTANTIALLY INHIBIT DECOMPOSITION OF SAIDKETONE PEROXIDE OF THE TYPE THAT LIBERATES GASEOUS BY-PRODUCTS ORDECREASED EFFECTIVENESS IN TERMS OF LENGTHENED GEL TIME OF MONOMERSINITIATED THEREWITH AND SAID KETONE PEROXIDE IS PRESENT IN THECOMPOSITION IN AN AMOUNT SUFFICIENT TO PROVIDE UP TO ABOUT 12.5 PERCENTACTIVE OXYGEN CONTENT TO SAID COMPOSITION.
 2. A storage stable loweralkyl ketone peroxide composition in accordance with claim 1 whereinsaid ketone peroxide is present in the composition in an amountsufficient to provide about 9.0 to 12.5 percent active oxygen content tosaid composition.
 3. A storage stable lower alkyl ketone peroxidecomposition in accordance with claim 1 wherein said stabilizer is vinylpyrrolidone and constitutes about 2 percent by weight of saidcomposition.
 4. A storage stable lower alkyl ketone peroxide compositionin accordance with claim 1 wherein said stabilizer is polyvinylpyrrolidone and constitutes about 2 percent by weight of saidcomposition.
 5. A storage stable lower alkyl ketone peroxide compositionin accordance with claim 1 wherein a said ketone peroxide is acoreaction product of Methyl ethyl ketone, 2,4-pentanedione, andhydrogen peroxide.